Due to an oil leak I have been sucking oil into the combustion chambers for about 1,500 +/- miles. After removing the intake and fixing the leak issue I noticed the intake ports and valves had some, not alot, of black residue and I can only assume the top of the pistons have the same residue/buildup.
Have any of you used a gas additive that REALLY cleans this gunk off? As I don't believe every commercial on T.V. I hope some of you can recommend a product that really works, if there is one.

fast idle in your driveway & slowly pour several ounces of diesel fuel in the carb & when your almost empty dump the last bit in to drown it & let it sit overnight then pull/clean the plugs so you can start it then take it out on the hiway & romp on it & may need to clean the plugs again when you are done. Seafoam would work also & save you the trouble of buying that small amt of diesel at a diesel pump

x2 on seafoam

trickle down the carb 3/4 can,dump the rest as engine shuts down,let sit,then run engine.

it will smoke very heavy for a bit but will stop in a bit,may want to change plugs after its done.

IIRC,thats what the directions on the can say,or add to tank of gas to do the samething while it lubes the upper engine,just takes longer.

seafoam is what ive been using for 30 plus years.

Seafoam main course with ATF as an occasional dessrt.

Okay, for those of you that have used Seafoam, or any other product, have you pulled your intake and/or heads to actually see if the product worked as advertised? Was everything pretty well cleaned up?

http://www.tk7thailand.com/TK7_questions_and_answers.htm Had great luck with TK7.Used for 10 years in a carbed pick-up,tore down carb and it was like new inside.Next to impossible to get the product since Iraq was using it in 1991 to fuel scud missles.

Back around 1998
I soaked eight 1994 Magnum 5.9L pistons in
Chevron Techron (not the current 'Plus' version of today),
Redline SI1,
Liqui-Moly Ventril Sauber (means valve cleaner in German),
Liqui-Moly Jectron,
Chrysler ATF+2,
Aircraft Paint Remover,
70% Walgreens propanol rubbing alcohol, and
Chevron Regular gasoline (not 10% ethanol back then)

The Libui-moly Ventril Sauber

http://www.liqui-moly.de/liquimoly/produktdb.nsf/id/en_1014.html?Opendocument&land=DE

did the best job removing carbon from the piston tops during my soak,
and Chevron Techron did second best,
but both took over two weeks to really remove 95% of the deposits.

The Liqui-Moly products used to be in stock at
VW and BMW dealerships,
and some auto parts stores in NC at least.
They were about 50% higher priced than Chevron back then.

the expensive Yamaha 'Ring Free' is supposed to be specially designed for this job too:

http://www.yamaha-motor.com/outboard/apparel/apscitemdetail/3/145/all/1/10007/detail.aspx

I also tried taking a second PCV valve and sucking the condensate water from the Ram's air conditioner system drain and injecting it into the intake through the 'test port' nipple on the driver's side of the 'Beer Barrel' factory Magnum intake.
This 'poor man's water injection' seemed to clean up carbon deposits,
reduce full throttle pinging
... but it hurt city driving MPG by about 2 MPG during the time I tried it,
which was about 3 months.
It also caused a noise that could be hear inside the pickup when the radio was off.

A $8 bottle of official
Chrysler Combustion Chamber cleaner
is a good manual de-carbonizer,
and appears to be a brown foam at least partly made of water.

I would rate Chrysler CCC as superior to Sea Foam.

Some years ago I read about a solvent for soaking aircraft engine used pistons to remove carbon deposits,
but I cannot find the link to the magazine article now. This solvent was alleged to do a very good job in less than a day of soaking.

If soaking, why not use good 'ole carburetor cleaner (the soaking type, not the aerosol)?

And what would happen if *that* was poured down the carb?

Personally, IMHO there's always a layer of carbon in there, and if it's just a dust-coating leave it be. If it's big chunks you'd want them gone, but then there's the risk of where they'd go.

And BTW - kerosene could be used instead of diesel?

Very soon after treating it will look the same as it does now.

Why bother?

Spraying water in carb at high idle works great. It steam cleans the chambers and tops of pistons.

This question comes up ever so often and the most obvious and proven product is overlooked. Most every outboard motor shop has de-carbonate products that are made for this and really work well.

Heck, even GM has a version of the same product called Upper Cylinder Cleaner. Most other manufacturers probably do too.

2 stroke engines used to have real problems with ring sticking due to carbon build up. They needed a product that worked. So for decades these products have been around. In fact, most outboard service schools recommend these products for use as a carb cleaner. The OMC stuff is all I have used as a carb cleaner for 25 years

It is available as a pour in can or in aerosol form. It is very gentle on aluminum and such, is water soluable and works by molecularly de-constructing the hydrocarbon links. It is not a corrosive.

I am surprised that something like this that works so well is often overlooked. It is designed for the very job of cleaning intake tracts and combustion chambers and works better than anything else.

Just saying.

Anyone have any data or stories on how
intake valve "gunk" deposits
have varied
individual cylinder to cylinder
air to fuel ratios?

Anyone ever flowbenched
a gunked up intake valve
versus a clean valve?

I have a strange one for ya - but it really works ....

If you buy a bag of small fine rice (hard stuff, not add watter and PUFF type) and very slowly feed it through the carb while running around 1500-2000 RPM, it will literally "blast" the inside of the combustion chambers clean.

Then follow up with a FOG of Sea-Foam, you get a great cleaning.

I did this and busted loose 10 years of crap out the back ...

You will need to change the oil and filter immediately following this.

I thought the old (ancient) guy was crazy that told me this - he is an old school mechanic from when they invented cars.. LOL

but - it worked.

Crazy I know - but a true thing.

Bill

That reminded of the old Bon Ami trick on Chevrolets to seat the rings or scuff the walls or something another

Shoulda tried that one on Cosworth Vega's...